1. Field of the Invention
The present invention relates to an apparatus for adjusting a height of control boxes, and more particularly to an apparatus for adjusting a height of control boxes, which is mounted on the left and right sides of a driver""s seat and adjusts a height of control boxes each installed with operation levers to enable a driver to drive with an optimal posture according to his body condition.
2. Description of Prior Art
In general, drivers operating heavy equipment repeat the same job for a long time in a specific posture and feel severe fatigue. In particular, in case that operation lever heights are not fit for various drivers"" bodies, the drivers"" fatigue becomes more serious, and, what is worse, the possibility of safety incidents goes up. Accordingly, diverse researches and developments have been performed on control levers and a height-adjusting apparatus of a levers-mounted control box.
A conventional apparatus for adjusting a height of control boxes, as shown in FIG. 1, adjusts the height of a the control box mounted on a vertical bar 3 with the linear movements of the vertical bar 3 through bevel gears 2a and 4a while an adjustment knob 1 is rotated.
However, in the conventional apparatus for adjusting a height of control boxes, a weight of a control box is loaded on a adjustment knob, so that a larger force is exerted to rotate the adjustment knob, what is worse, causing a problem damaging gears by the larger force.
Further, in the prior art, an height-adjusting apparatus is installed on the left and right sides, respectively, for the left and right control boxes, so the heights of the left and right control boxes can not be adjusted to the position of the same level.
It is an object of the present invention to provide an apparatus for adjusting heights of control boxes which prevents control box weights from being directly loaded on an adjustment knob and enables easy adjustments with less force.
It is another object of the present invention to provide an apparatus for adjusting heights of control boxes which enables the left and right control boxes of a driver"" seat to be adjusted to the same height.
In order to achieve the above objects, the present invention comprises a base plate mounted on the bottom of a driver""s seat; a pair of upper arms and a pair of lower arms, the upper side of one upper arm being hinged to the upper side of another upper arm by a first pin, the lower side of one lower arm being hinged to the lower side of another lower arm by a second pin, and the lower sides of the pair of upper arms being hinged to the upper sides of the pair of lower arms by adjustment pins respectively; an adjustment shaft screw-coupled to at least one of the adjustment pins and having spirals adjusting a distance between the adjustment pins when rotating; and a first rotary arm one end of which is vertically fixed to one end of a rotation bar rotatably supported by the base plate and the other end of which is coupled to one of the first and second pins, a pin of the first and second pins which is not coupled being fixed to the based plate and the first rotary arm being coupled to one control box.
In an embodiment of the present invention, the base plate further comprises a rotation shaft for the control boxes, so that the control boxes rotates about the rotation shaft for the control boxes.
In another embodiment of the present invention, a second rotary arm being symmetrical to the first rotary arm and one end of which is fixed to the other end of the rotation bar is further included to adjust a height of the other control box coupled to the second rotary arm to be equal to a height of the one control box.
In another embodiment of the present invention, a motor coupled to the adjustment shaft, equipped with a control switch, and rotating the adjustment shaft is further comprised, so that the height of control boxes is adjusted by operating the motor.